In Finland, it is customary for children to line up their shoes outside the classroom and to learn in their stockinged feet. Outside classroom 3C at Laakavuori primary in Helsinki, there are only four pairs of shoes and they include the scuffed trainers of a 12-year-old boy and the sparkly pumps of a seven-year-old girl.

Inside, four children – Anastasia, Artur, Kevin and Arthur – are taking in the basics of the Finnish language. Their teacher points at a picture of a jacket and articulates the word slowly – "takki". The children mouth it back. A teaching assistant, sitting at the back, joins in.

Anastasia, Artur, Kevin and Arthur arrived in Finland with their families less than two months ago. Like most newcomers here, they come from Russia and Estonia. Fortunately for them, their parents have chosen a country that has much to teach other nations when it comes to educating young immigrants.

Finland is seen by many outsiders as monocultural – its foreign-born citizens make up just 5% of its population, compared to about 11.5% in the UK. But, over the last 15 years, Finland has diversified at a faster rate than any other European country. By 2020, a fifth of Helsinki's pupils are expected to have been born elsewhere – the majority in Russia, Estonia, Somalia and the former Yugoslavia.

At Laakavuori primary, in the poorer, eastern part of Helsinki, 45% of pupils have a language other than Finnish as their mother tongue. And yet they achieve as much as others in more affluent areas of the country, where there are few, if any, immigrants.

Politicians and policy-makers the world over have admired Finland's education system for the fact that, over the last decade, its 15-year-olds have consistently had the highest – or among the highest – standards in reading, maths and science when compared with most of the developed countries of the world. Every three years, the Organisation for Economic Co-operation and Development (OECD) administers a numeracy, literacy and science test to about 470,000 15-year-olds in 65 countries, known as the Programme for International Student Assessment. In the most recent Pisa study, in 2009, Finland came third out of 65 countries, while the UK was 25th. In the 2006 Pisa study, Finland came top and the UK 14th.

Much of Finland's success has been attributed to the high prestige associated with being a teacher and the fact that it is as hard for Finns to win a place on a teacher training course as it is for them to get into law or medical school.

But another aspect of Finland's success – getting children whose first language is not Finnish up to the high standards of their classmates – appears to have been overlooked by the education tourists.

Anastasia, Artur, Kevin and Arthur stay in their class of four with a teacher and teaching assistant for 25 hours a week – for every subject except sports and arts. It can be anything between six months and a year before they are judged to have mastered Finnish and are ready to be placed into their correct year group.

It's no surprise that with this kind of immersion, half of Laakavuori's pupils – including a high proportion of those who come not speaking a word of Finnish – go on to pass the aptitude test that admits them to prestigious academic high schools.

It says something, too, about Finland's attitude that since the 1980s, the state has paid for Somali teachers to help young Somalis living in Finland to expand their vocabulary in their native language, too.

Helsinki's education department estimates that just over 11,000 pupils – almost 2% – have state-funded tuition in a mother tongue that isn't Finnish, before or after their other classes.

In England, meanwhile, a grant for schools to employ and train teachers to help pupils whose first language is not English has been scrapped.

Finland, on the other hand, has had what it describes as a "positive discrimination" policy since the 1990s. It gives schools extra funds if they are situated in relatively poor areas or have a disproportionately high number of children with special needs. It tops up these funds with €1,000 (£875) a year for each child on the school's roll who has lived in Finland for less than four years.

"The government rightly recognises that it is more intensive to teach in an area like my school," says Janne-Pekka Nurmi, principal of Laakavuori.

This sounds just like a more generous version of our pupil premium – the £488 that schools in England receive annually for each pupil they enrol who is eligible for free school meals. But there's a crucial difference. From next September, our government will be publishing what schools spend this on and, in time, will publish its suggestions of how best the pupil premium can be spent. In Finland, they simply leave it to the teachers.

Laakavuori primary has used this premium to employ social workers and psychologists a few days a week. The principal says this helps to "detect early problems and deal with them quickly".

It's not just in primary schools that young immigrants are helped. Helsinki's education department is running a pilot project that puts 15- and 16-year-old immigrants in touch with "social instructors" to ensure they fit in with Finnish society and don't drop out of school. Extraordinarily, these instructors work to find the young people friends to socialise with as well as helping them to find the services and careers advice they need.

Naldic (National Association for Language Development in the Curriculum) represents teachers in UK schools who specialise in educating pupils whose first language is not English. Amy Thompson, its chair, says that in England, the needs of non-English-speaking young immigrants are "no longer recognised as distinct from the needs of all pupils in terms of policy and funding". "The English system of 'sink or swim' needs to be brought in line, not only with Finland, but with English-speaking countries across the world that provide dedicated funding, curriculum and support for learners for whom English is an additional language," she says.

To many, a comparison between Finland and the UK is unfair. Finland's entire pupil population amounts to just 600,000, while that of England and Wales tops 7 million. Finland wants to promote skilled immigrants to compensate for an emerging labour shortage due to its ageing population, while in England, the aim is to reduce net migration to under 100,000 by 2015.

In Finland, unlike in the UK, an influx of immigrants is still new to the country.

Not everyone in Finland is quite so friendly towards newcomers. In April, The Finns – a populist nationalist party that wants to limit humanitarian immigration to refugee quotas – won 19% of the vote in the parliamentary election, becoming the largest opposition party in Finland.

A growing number of Finns are said to be removing their children from ethnically diverse primary schools, and some are reported to be demanding a cap on the number of non-Finns in a classroom.

But Finland's teachers and educationists are adamant that they will fight this on all fronts. They say that what they provide for young immigrants works.

Meanwhile, says Thompson, England should look at Finland's impressive procedures for the education of bilingual pupils. A national survey carried out by Naldic and the National Union of Teachers in February found that over 60% of respondents believed that support for pupils for whom English was an additional language and for bilingual learners had significantly deteriorated over the last six months. In England, she says, "the situation is becoming worse by the day".

Finland, the facts

• Parents can send children aged between eight months and five years to free daycare. At age six, there is a year of pre-school

• All full-time pupils get free lunches

• Basic compulsory education starts at age seven and ends at age 16

• At 16, pupils either go to vocational school or an upper secondary school. Upper secondary schools tend to be for those who want to go on to university, although it is possible to study for degrees from vocational schools

• There are no league tables or inspections and the only national exam is at the age of 18 or 19